Grinding mill bolted construction

ABSTRACT

A grinding mill drum structure comprises a bolted shell having a plate liner bolted to a drum inner face by means of a composite bolting arrangement wherein a smaller diameter bolt securing the plate liner extends through the shank of a larger bolt that secures the structure of the drum, with nuts for both fasteners available from the outside of the drum, to particularly facilitate servicing and maintenance.

United States Patent Smallwood et al.

GRINDING MILL BOLTED CONSTRUCTION Inventors: Robert Edwards Smallwood, Pointe Claire, Quebec; Marvin Bruce Shaver, Beaconsfield, Quebec, both of Canada Dominion Engineering Works, Limited, Lachine, Quebec, Canada Filed: Aug. 24, 1973 Appl. No.: 391,302

Related US. Application Data Continuation-impart of Ser. No. 216,471, Jan. 10, 1972, abandoned.

Assignee:

US. Cl. 241/182, 241/181 Int. Cl. B02c 17/22 Field of Search 241/176, 179, 181, 182

[ Oct. 29, 1974 [56] References Cited UNITED STATES PATENTS 1,899,015 2/1933 Corbishley 241/182 2,114,640 4/1938 Rumbarger et al 241/182 X 2,687,230 8/1954 McPherson 241/182 X Primary ExaminerRoy Lake Assistant Examiner-E. F. Desmond [5 7 ABSTRACT A grinding mill drum structure comprises a bolted shell having a plate liner bolted to a drum inner face by means of a composite bolting arrangement wherein a smaller diameter bolt securing the plate liner extends through the shank of a larger bolt that secures the structure of the drum, with nuts for both fasteners available from the outside of the drum, to particularly facilitate servicing and maintenance.

3 Claims, 6 Drawing Figures GRINDING MILL BOLTED CONSTRUCTION This is a continuation-in-part of application Ser. No. 216,471 filed .Ian. IO, I972, now abandoned.

This invention is directed to a fastening arrangement as used in a composite drum structure for a grinding mill.

In the construction of large machines such as griding mills problems arise in providing economic fastening means to permit ready assembly and disassembly of multilayered construction.

A case in point, the construction of a grinding mill for the reduction of friable material, requires the provision of structural means to secure the shell of the mill together, and additional provision for securing liners within the shell to withstand operational wear.

The present invention provides a composite bolting arrangement having provision to permit the securing of the shell structure element by hollow bolt fasteners, with subsequent attachment of the shell liner elements to the shell by way of cooperating bolt fasteners extending through the hollow bolts and attached thereto.

In the erection of composite mill structures wherein the mill drum is provided with bolted structure including trunnions bolted to the end of the mill, and wherein wear plates of cast construction are bolted to the inside of the mill shell, problems are experienced in securing the multiple layered structure in readily disassembled relation, and an inordinate amount of drilling and bolt ing is encountered.

The adoption of a composite bolt permitting sequential assembly of plural layers of structure has the particular advantage that the laying out, marking and ma chining of machine components is simplified and reduced, while the number of penetrations of the structure members is minimised, with a corresponding gain in structural integrity.

The present invention thus provides in combination fastening devices in a composite structure having a plurality of members in mutual overlying relation, the fastening devices each having a first hollow bolt means extending within a bore through at least two of the overlying members, and a nut to secure the fastening means with two members in mutual securing relation, and a second fastening means engaging a third structure member in secured relation thereto, the second fastening means extending into the first fastening means in secured relation therewith, whereby the three structure members are secured in mutual fixed relation by way of a single penetration of each of the members at each bolt location.

Certain embodiments of the invention are described, reference being had to the accompanying drawings, wherein;

FIG. I is a general view of a portion of a grinding mill churn embodying the present invention;

FIG. 2 is a partial diametral section of the mill drum of FIG. 1;

FIG. 3 is an enlarged view of the circled portion 3 of FIG. 2;

FIG. 4 is a view taken at 4-4 of FIG. 2 showing a number of bolt locations;

FIG. 5 is a section view at 5-5 of FIG. 3; and

FIG. 6 is a section view at 6-6 of FIG. 3.

FIG. I somewhat schematically represents the drum I ofa mill having a feed chute 12 to admit ore or other material for passage through a hollow trunnion 14 to the mill interior. The mill drum 10 is supported for rotation about trunnion 14, 16 by pedestal mounted bearings (not shown).

In the section illustrated in FIG. 2 is seen the conical head section 18 of the shell end, having an annular plate or casting 20 to which the trunnion I4 is secured by way of flange 22. Within the head section 18 cast liner plates 24 also are secured thereto. The lifter plates 26 do not constitute part of the present invention, although securing means to assemble the lifters 26 to the drum 10 can follow the practice as set forth herein.

Referring to FIG. 3, the plate 20 has a bore 30 extending therethrough, having an enlarged shaped recess 32 in the inside face thereof. A bore 34 in the flange 22 is aligned with the bore 30, to receive a first hollow bolt 36. The fixed head 38 of bolt 36 is received within the shaped recess 32, to preclude turning of the bolt and a securing nut 40 serves to secure the flange 22 in tight bolted relation with the plate 20.

The case liner plate 24 is provided with a cored recess 42 shown as having a square cross-section within which the head portion 44 of a second bolt 46 is received. The second bolt 46 extends through a bore 48 in the first bolt 36, and is secured thereto by a securing nut 50.

The provision of a torque slot 52 in the outer face of the second bolt 46 as an alternative to the shaped recess 42, permits tightening of the: nut 50 while maintaining the bolt 46 stationary.

It will be understood that in alternative exemplifications the provision of recesses to receive the head portions of the respective bolts may be obviated by providing internal threading in the respective bores and utilising cap screws or threaded studs or equivalent fasteners in place of the respective bolts. A further contemplated variation is the provision of a partial or even a complete recess for the head 38 of the first bolt in the adjacent face of the liner 24.

We claim:

1. A grinding mill hollow drum structure having at least three layers of plate in overlying substantially sandwiched relation, with an inner, an intermediate and an outer plate member, said inner and said intermediate plates abutting at an interface, each said plate having a plurality of spaced holes therein in aligned relation with corresponding holes in the other plates, including a recess at said interface, fastening means securing the plates together, comprising hollow bolt means having a head portion secured in said interface recess and a tensioning head portion accessible from outside the drum for releasably securing said intermediate and outer members in mutual pressing relation, and inner bolt means withdrawable through said hollow bolt means having an outer tensioning head portion accessible from outside the drum to draw said inner plate towards said intermediate plate, being releasable from without the drum whereby said inner plate may be withdrawn within the drum while maintaining the other said plates in secured relation.

2. The structure as claimed in claim 1 wherein said plate recess is provided extending from the interface of tion extending outwardly of said hollow bolt means. 

1. A grinding mill hollow drum structure having at least three layers of plate in overlying substantially sandwiched relation, with an inner, an intermediate and an outer plate member, said inner and said intermediate plates abutting at an interface, each said plate having a plurality of spaced holes therein in aligned relation with corresponding holes in the other plates, including a recess at said interface, fastening means securing the plates together, comprising hollow bolt means having a head portion secured in said interface recess and a tensioning head portion accessible from outside the drum for releasably securing said intermediate and outer members in mutual pressing relation, and inner bolt means withdrawable through said hollow bolt means having an outer tensioning head portion accessible from outside the drum to draw said inner plate towards said intermediate plate, being releasable from without the drum whereby said inner plate may be withdrawn within the drum while maintaining the other said plates in secured relation.
 2. The structure as claimed in claim 1 wherein said plate recess is provided extending from the interface of said inner plate with said intermediate plate inner face to receive a bolt head of said hollow bolt means in non-rotational relation therein, to permit said inner plate to abut the intermediate plate.
 3. The structure as claimed in claim 2 wherein said inner bolt means includes a threaded nut-receiving portion extending outwardly of said hollow bolt means. 